fix: add enum in socialType

Author: yayo0

lib/domain/use-cases/delete_user_use_case.dart

@@ -1,5 +1,6 @@
 import 'package:injectable/injectable.dart';
 import 'package:on_time_front/domain/repositories/user_repository.dart';
+import 'package:on_time_front/presentation/shared/constants/constants.dart';
 
 @Injectable()
 class DeleteUserUseCase {
@@ -12,10 +13,11 @@ class DeleteUserUseCase {
       await _userRepository.postFeedback(feedbackMessage);
     } catch (_) {}
 
-    final socialType = await _userRepository.getUserSocialType();
-    if (socialType == 'GOOGLE') {
+    final socialTypeString = await _userRepository.getUserSocialType();
+    final socialType = socialTypeFromString(socialTypeString);
+    if (socialType == SocialType.google) {
       await _userRepository.deleteGoogleUser();
-    } else if (socialType == 'APPLE') {
+    } else if (socialType == SocialType.apple) {
       await _userRepository.deleteAppleUser();
     } else {
       await _userRepository.deleteUser();

lib/presentation/shared/constants/constants.dart

@@ -5,3 +5,33 @@ enum PreparationStateEnum {
   now, // 진행 중
   done, // 완료됨
 }
+
+enum SocialType {
+  normal,
+  google,
+  apple,
+}
+
+SocialType socialTypeFromString(String? value) {
+  if (value == null) return SocialType.normal;
+  final normalized = value.trim().toLowerCase();
+  switch (normalized) {
+    case 'google':
+      return SocialType.google;
+    case 'apple':
+      return SocialType.apple;
+    default:
+      return SocialType.normal;
+  }
+}
+
+String socialTypeToString(SocialType type) {
+  switch (type) {
+    case SocialType.normal:
+      return 'normal';
+    case SocialType.google:
+      return 'google';
+    case SocialType.apple:
+      return 'apple';
+  }
+}